Befuddle (7)
I believe the answer is:
confuse
'befuddle' is the definition.
(I know that befuddle can be written as confuse)
This is all the clue.
(Other definitions for confuse that I've seen before include "Puzzle" , "Perplex" , "Muddle, mix up" , "Disconcert, befuddle" , "Bewilder" .)